1. Field of the Invention
The present invention relates to an RFID (Radio Frequency Identification) tag which is a tag for use in article management, etc. provided with an antenna for transmission and reception and an IC chip for signal write and read and its manufacturing method.
2. Related Art
RFID tags have been used conventionally in article management, etc. Each of the RFID tags is provided with an antenna coil and elements such as an IC connected to the antenna coil, activated by receiving a signal with a predetermined frequency transmitted from an interrogator in the antenna coil, thereby driving the elements such as an IC, communicates with the interrogator, and carries out article management or the like by reading data stored in the IC element, while writing new data in the IC element. The RFID tag are generally attached to a surface of an article to use, and as a structure of the antenna coil to stabilize frequency characteristics when the article is metal, such a structure is proposed that a coil is wound on the outer periphery of a magnetic core (for example, see FIGS. 5 and 6 in JP 2000-101471).
Further, in order to solve the problem that the entire antenna becomes relatively thick when the coil is wound on the outer periphery of the magnetic core as described above, such an RFID tag is proposed that a meandering conductive material is formed on an FPC, a slits are provided between the conductive material, and plane-shaped magnetic cores are inserted into the slits alternately in right and back sides to form an antenna coil (for example, see JP2002-117383).
However, the conventional RFID tags have following problems in terms of efficient manufacturing. In other words, in the RFID as described in patent document 1, in winding the conductive material around the magnetic core, the winding speed is not increased when the magnetic core is a flat plate, and there are limitations in increasing the productivity, resulting in an obstacle to cost reduction in a recent situation where thinning of RFID tags is requested.
Further, in the RFID as described in JP2002-117383, it is necessary to suck the FPC with a vacuum suction apparatus when inserting the plane-shaped magnetic cores into the slits, a large-scale apparatus is required for the manufacturing, and there are limitations in increasing efficiency of the manufacturing.
Furthermore, when an RFID tag is attached to a metal article to use, there arises a problem that frequency characteristics fluctuate due to the interaction between the metal article and the antenna coil. As measures against the fluctuations of the frequency characteristics, it is considered to place a metal plate for shielding inside the FRID tag, but the size of the RFID tag increases, while the cost is also increased, and in these respects, there are significant disadvantages.